This invention relates to an apparatus which accurately identifies contaminants in the aqueous humor of a human eye.
Examination of the aqueous humor is a routine part of every eye examination. This reflects the realization by the clinician that alterations of the humor are a cardinal sign of disease, that the nature and magnitude of an observed change is a useful gauge of the type and severity of disease, and that the state of the aqueous is a useful monitor of the response to therapy. Alterations from normally clear aqueous humor occur in association with a variety of ocular diseases, e.g, infections, traumas and inflammations. Many of these diseases are major causes of visual loss. However, if detected early and properly diagnosed, such diseases can often be treated successfully to prevent further or permanent visual loss.
Accurate characterization of the composition of aqueous humor contaminants provides a basis for precise diagnosis of an ocular disease. Unfortunately, currently available techniques for analyzing aqueous contaminants often leave a lot to be desired.
For example, one known technique for accurately determining the composition of contaminants involves physical invasion of the examined eye with a syringe. This provides the much-needed information as to the types of aqueous contaminant, but involves a surgical procedure which carries some risk to the eye and which may itself alter the aqueous being studied. For this reason, such invasive samples are seldom taken without an urgent need for the results and are seldom repeated to follow the course of disease.
A need, therefore, exists for techniques which provide accurate identification and quantitation of aqueous humor contaminants by "non-invasive" examination of the human eye. As used herein, the term "non-invasive", in connection with the examination of a human eye, denotes examination of the eye which maintains the integrity of the cornea, i.e., where the tissue of the cornea is not ruptured.
Some non-invasive techniques have recently been invented for detecting changes in aqueous humor. One such technique, shown in U.S. Pat. No. 3,963,019 to Quandt, utilizes a beam of light projected through a patient's eye. An analyzer is positioned to detect the beam on its exit from the examined eye and compares the effect the aqueous humor had on the refraction of the beam against a norm. While the comparison roughly indicates a change in the glucose level in the aqueous humor, it does not characterize the macromolecules or cells of any aqueous contaminant.
Accordingly, it is the primary object of the present invention to provide a technique for analyzing the composition of contaminants in aqueous humor by non-invasive measurement of an examined eye.
It is a further object to provide a technique which accurately identifies and quantitates macromolecular or cellular contaminants in aqueous humor.
It is another object to provide a technique having the above-listed advantages, which can be used clinically with no greater risk or discomfort to the patient than routine slit-lamp gonioscopy.
It is yet another object to provide a technique for accurately identifying aqueous contaminants that is simple in design and easy to use.
These and other objects of the invention, as well as many of the attendant advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings.